(1) Field of the Invention
This invention relates to electrical devices and, more particularly, to battery terminals and electrical conductors molded of conductive loaded resin-based materials comprising micron conductive powders, micron conductive fibers, or a combination thereof, substantially homogenized within a base resin when molded. This manufacturing process yields a conductive part or material usable within the EMF or electronic spectrum(s).
(2) Description of the Prior Art
Portable electrical and electronic devices are widely used in industrial and consumer applications. A common feature in most of these portable devices is a battery power source. Battery power sources comprise a means of storing energy in chemical form and releasing this energy as electrical power upon demand from the portable device. In a typical battery source, a set of dissimilar elemental electrodes are held in an electrolyte. When an electrical demand is placed across the electrodes, an internal electrochemical reaction occurs between the electrodes and the electrolyte. This electrochemical reaction generates free electrons at a voltage potential as a by-product.
In most cases, it is assumed that the battery, even if it is rechargeable, is a replaceable component of the portable electrical or electronics system. Therefore, the battery must be designed for handling and for replacement. In many cases, the electrode materials that are used in the electrochemical reaction are not appropriate for external use because the material is expensive, hazardous, and/or does not have optimal properties of hardness or electrical conductivity. For example, lead may serve as an electrode material in a lead-acid battery as is commonly found in motor vehicle applications. However, it is common for the external terminals, or contact terminals, of a lead-acid battery to be constructed of another metal material or of a metal alloy that exhibits better conductivity than lead while reducing the hazardous properties of lead exposure. Similarly, in various portable batteries, the external contact points for the battery are typically formed of very conductive metals or alloys that contact the internal electrode materials either directly or via a conductive paste.
A typical problem for various types of batteries is that of corrosion. The corrosive chemical conditions that cause reactions to occur at the internal electrodes also present a corrosive environment for the external electrodes. In addition, external environmental conditions of portable operation tend to increase corrosive. In a motor vehicle, for example, external conditions of moisture, road and sea salt, and vehicle fluids, combine with the inherent voltage conditions to cause rapid electro-voltaic corrosion of the battery electrodes and cables. Corrosion of these components causes many reliability concerns. A key objective of the present invention is to provide external battery terminals, contacts, and conductors combining excellent electrical performance with excellent corrosion resistance.
Several prior art inventions relate to battery applications and to conductive plastics. U.S. Pat. No. 5,685,632 to Schaller et al describes a flashlight wherein structural components comprise conductive plastic such that these structural components complete the lighting circuit. The conductive plastic may comprises a resin material with metal filler. U.S. Pat. No. 5,716,243 to Kourimsky teaches a connector assembly used to connect to terminals of an automotive battery. U.S. Pat. No. 4,098,967 to Biddick et al describes a lead-acid type battery. Conductive plastic is used in each cell to form a protective layer between active elements. Metal (Pb) sheets are bonded to the conductive plastic on the end cells to form terminal connections. The conductive plastic uses carbon fiber. U.S. Pat. No. 6,342,680 to Nakagawa et al teaches a lead-free, super-highly conductive plastic formed from a conductive resin composition. The conductive resin comprises a thermoplastic resin, a lead-free solder that melts during plasticization, and metal powder or a mixture of metal powder and metal short fibers.